The UC San Diego Superfund Basic Research Program will identify and characterize molecular events that contribute to the onset of environmental disease resulting from exposure to Superfund site contaminants. In the course of studies in Projects 1, 4, 5, 6 and 7, genes with altered patterns of gene expression after exposure to Superfund site chemicals will be identified. To understand the function of these novel genes in vivo, the Mouse Genetics and Phenotyping Core will produce mice with altered expression patterns of these genes, and assist investigators in the analysis of the phenotypes of these mutant mice. It is anticipated that the organization structure of this Core will foster collaborations among the five projects producing and characterizing mutant mice. The specific aims of the Mouse Genetics and Phenotyping Core are to: 1) aid in the design and production of knock-out and transgenic mice; 2) provide expertise in husbandry of these mutant mouse strains, including breeding the mice to be sure that the mutant allele is transmitting through the germline, and to homozygosity for knock-outs; 3) maintain mice as inbred strains, and provide other inbred strains to produce relevant hybrid backgrounds; 4) in close conjunction with the investigator, perform a phenotyping screen on each of the mutant strains that will include histopathology, anatomic pathology, blood and urinalysis, and physiological monitoring; 5) assist the investigator in a further analysis of phenotypes when detected.